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#ifndef UTIL_STREAM_CHAIN__
#define UTIL_STREAM_CHAIN__
#include "util/stream/block.hh"
#include "util/stream/config.hh"
#include "util/stream/multi_progress.hh"
#include "util/scoped.hh"
#include <boost/ptr_container/ptr_vector.hpp>
#include <boost/thread/thread.hpp>
#include <cstddef>
#include <assert.h>
namespace util {
template <class T> class PCQueue;
namespace stream {
class ChainConfigException : public Exception {
public:
ChainConfigException() throw();
~ChainConfigException() throw();
};
class Chain;
// Specifies position in chain for Link constructor.
class ChainPosition {
public:
const Chain &GetChain() const { return *chain_; }
private:
friend class Chain;
friend class Link;
ChainPosition(PCQueue<Block> &in, PCQueue<Block> &out, Chain *chain, MultiProgress &progress)
: in_(&in), out_(&out), chain_(chain), progress_(progress.Add()) {}
PCQueue<Block> *in_, *out_;
Chain *chain_;
WorkerProgress progress_;
};
// Position is usually ChainPosition but if there are multiple streams involved, this can be ChainPositions.
class Thread {
public:
template <class Position, class Worker> Thread(const Position &position, const Worker &worker)
: thread_(boost::ref(*this), position, worker) {}
~Thread();
template <class Position, class Worker> void operator()(const Position &position, Worker &worker) {
try {
worker.Run(position);
} catch (const std::exception &e) {
UnhandledException(e);
}
}
private:
void UnhandledException(const std::exception &e);
boost::thread thread_;
};
class Recycler {
public:
void Run(const ChainPosition &position);
};
extern const Recycler kRecycle;
class WriteAndRecycle;
class Chain {
private:
template <class T, void (T::*ptr)(const ChainPosition &) = &T::Run> struct CheckForRun {
typedef Chain type;
};
public:
explicit Chain(const ChainConfig &config);
~Chain();
void ActivateProgress() {
assert(!Running());
progress_.Activate();
}
void SetProgressTarget(uint64_t target) {
progress_.SetTarget(target);
}
std::size_t EntrySize() const {
return config_.entry_size;
}
std::size_t BlockSize() const {
return block_size_;
}
// Two ways to add to the chain: Add() or operator>>.
ChainPosition Add();
// This is for adding threaded workers with a Run method.
template <class Worker> typename CheckForRun<Worker>::type &operator>>(const Worker &worker) {
assert(!complete_called_);
threads_.push_back(new Thread(Add(), worker));
return *this;
}
// Avoid copying the worker.
template <class Worker> typename CheckForRun<Worker>::type &operator>>(const boost::reference_wrapper<Worker> &worker) {
assert(!complete_called_);
threads_.push_back(new Thread(Add(), worker));
return *this;
}
// Note that Link and Stream also define operator>> outside this class.
// To complete the loop, call CompleteLoop(), >> kRecycle, or the destructor.
void CompleteLoop() {
threads_.push_back(new Thread(Complete(), kRecycle));
}
Chain &operator>>(const Recycler &) {
CompleteLoop();
return *this;
}
Chain &operator>>(const WriteAndRecycle &writer);
// Chains are reusable. Call Wait to wait for everything to finish and free memory.
void Wait(bool release_memory = true);
// Waits for the current chain to complete (if any) then starts again.
void Start();
bool Running() const { return !queues_.empty(); }
private:
ChainPosition Complete();
ChainConfig config_;
std::size_t block_size_;
scoped_malloc memory_;
boost::ptr_vector<PCQueue<Block> > queues_;
bool complete_called_;
boost::ptr_vector<Thread> threads_;
MultiProgress progress_;
};
// Create the link in the worker thread using the position token.
class Link {
public:
// Either default construct and Init or just construct all at once.
Link();
void Init(const ChainPosition &position);
explicit Link(const ChainPosition &position);
~Link();
Block &operator*() { return current_; }
const Block &operator*() const { return current_; }
Block *operator->() { return ¤t_; }
const Block *operator->() const { return ¤t_; }
Link &operator++();
operator bool() const { return current_; }
void Poison();
private:
Block current_;
PCQueue<Block> *in_, *out_;
bool poisoned_;
WorkerProgress progress_;
};
inline Chain &operator>>(Chain &chain, Link &link) {
link.Init(chain.Add());
return chain;
}
} // namespace stream
} // namespace util
#endif // UTIL_STREAM_CHAIN__
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